A PurpleAir air quality monitoring sensor was installed at multiple sites within the CT DEEP monitoring network to evaluate the sensors performance tracking PM2.5 data against a reference. PurpleAir data was corrected using the extended U.S-wide correction equation developed by the EPA to reduce bias in sensor data (more information found here: AirNow). Hourly data from 2023 was then compared to a T640 reference monitor located at the same location. The full dataset used can be downloaded here Download CSV.

Site Locations

Sensor Details

PurpleAir Specifications

Possible Configuration Evaluated Configuration Cost Data Access Power Supply Considerations Reference Monitor Compared
PM2.5, Temperature, Relative Humidity, Pressure PM2.5 Sensor: $229
Outdoor Power Supply: $40
Potted 5V USB outdoor power supply 12 ft mains plug Micro SD card, WiFi connectivity, API download and live public online map Effected by saltwater (issues with coastal use), Life Expectancy ~2 years, laser counters may need replacements PM2.5: Teledyne API T640X
Temp & RH: AutoMet 580

Setup


Timeseries Comparison

PurpleAir hourly data for PM2.5 were compared by quarter to reference values from a T640 analyzer (Q1: January-March, Q2: April-June, Q3: July-September, Q4: October-December).

Bridgeport

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Cornwall

Quarter 1

Quarter 2

Quarter 3

Quater 4

Danbury

Quarter 1

Quarter 2

Quarter 3

Quarter 4

East Hartford

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Groton

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Hartford

Quarter 1

Quarter 2

Quarter 3

Quarter 4

New Haven

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Waterbury

Quarter 1

Quarter 2

Quarter 3

Quarter 4

Correlation Comparison

PurpleAir and Reference Correlation

Bridgeport

Cornwall

Danbury

East Hartford

Groton

Hartford

New Haven

Waterbury

Results Summary